Quarterly Data (Unaudited) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Quarterly Data (Unaudited)
Net sales	$ 7,089	$ 7,531	$ 7,680	$ 7,311	$ 6,709	$ 6,874	$ 6,731	$ 6,348	$ 29,611	$ 26,662	$ 23,123
Cost of sales	3,824	4,027	4,040	3,802	3,575	3,583	3,435	3,238	15,693	13,831	12,109
Net income attributable to 3M	954	1,088	1,160	1,081	928	1,106	1,121	930	4,283	4,085	3,193
Earnings per share attributable to 3M common shareholders - basic (in dollars per share)	$ 1.36	$ 1.54	$ 1.63	$ 1.52	$ 1.30	$ 1.55	$ 1.57	$ 1.31	$ 6.05	$ 5.72	$ 4.56
Earnings per share attributable to 3M common shareholders - diluted (in dollars per share)	$ 1.35	$ 1.52	$ 1.60	$ 1.49	$ 1.28	$ 1.53	$ 1.54	$ 1.29	$ 5.96	$ 5.63	$ 4.52
Decrease in 3M's net income resulting from the March 2010 enactment of the Patient Protection and Affordable Care Act, including modifications made in the Heath Care and Education Reconciliation Act of 2010										$ 84
Decrease in 3M's net income resulting from the March 2010 enactment of the Patient Protection and Affordable Care Act, including modifications made in the Heath Care and Education Reconciliation Act of 2010 (in dollars per diluted share)										$ 0.12